Romney largely unscathed from debate attacks

A tightened field vying for the Republican nomination took aim at frontrunner Mitt Romney in a fiery debate just days before South Carolina's presidential primary.

Before a raucous audience, the four candidates lagging behind Mr Romney in polls ahead of Saturday's key vote sought, and largely failed, to land damaging blows on the former Massachusetts governor.

Ex-House speaker Newt Gingrich, who is trailing in the battle to be the party's standard-bearer in the November election against president Barack Obama, came out swinging.

Mr Romney should answer questions about his time as a venture capitalist with a company called Bain Capital, Mr Gingrich said, after Mr Romney's rivals slammed him for buying out firms to leave them bankrupt and reap the rewards.

"There was a pattern in some companies, a handful of them, with leaving them with enormous debt, and then within a year or two or three having them go broke," Mr Gingrich said.

"I think that is something he ought to answer."

But Mr Romney hit back against the attacks, led in a kind of pincer movement between Mr Gingrich and former senator Rick Santorum.

Field narrows

The most moderate candidate in the race, Mr Huntsman ended his struggling White House bid and called on Republicans to unite in support of Mr Romney, who has already won the first two 2012 nominating contests in Iowa and New Hampshire.

Mr Huntsman's departure left hardened social conservatives Mr Santorum, Mr Gingrich and Texas governor Rick Perry, hoping the evangelical base in South Carolina will swing in their favour, along with Texas congressman Ron Paul.

Under pressure from Mr Gingrich and Mr Perry, Mr Romney was called on to release his tax records, and said he may do later in the year, but resisted making a firm promise.

Stumble

Mr Perry meanwhile, in a foreign policy stumble, stood out in the debate for describing Turkey, a key US ally, as a state "ruled by Islamic extremists".

Mr Gingrich was able to stir up support from the audience, who at one point gave him a standing ovation when pressed on his stance to boost child employment.

According to a new CNN/ORC poll, Mr Romney and Mr Obama are in a dead heat, with the Republican taking a slight 48-47 per cent edge among registered voters, and Mr Obama ahead among all respondents, 49-47 per cent.

The president has the advantage over Mr Gingrich, Mr Santorum and Mr Paul, according to the poll.

But the president's approval rating slumped to 47 per cent from 49 per cent a month before.